In general, the reliability of reblooming iris declines as you go farther north. Gardeners in Zones 3 and 4 may see little or no reblooming. In most types, the reblooming cycle is set off by cooler weather, so if your temperatures are tropical year-round, you may not see a second bloom. Also, some varieties won’t start reblooming for a couple of years.
Where to Plant Reblooming Iris
Plant reblooming iris in a sunny spot that gets shade later in the day. Make sure they aren’t overshadowed by other plants that can prevent them from getting the light they need. Reblooming iris does very well in its own spot, away from other flowers.
How and When to Plant Reblooming Iris
Plant reblooming iris rhizomes 1 to 2 feet apart, with the tops exposed and the roots beneath the soil. Plant in late summer or early fall, when nighttime temperatures are no lower than 50ºF, to give the roots plenty of time to get established before spring blooming. Once they’re established, reblooming iris will grow very fast.
Reblooming Iris Care Tips
Because they’re doing more work throughout the growing season, reblooming iris need more attention than regular varieties.
Light
Reblooming iris should be located where they get sun most of the time, with some shade later in the afternoon, especially in hot climates.
Soil and Water
Reblooming iris likes well-drained soils. If the soil in your garden is heavy, add coarse sand or humus to help with drainage. Reblooming iris needs fertile and slightly acidic soil. Water every other week to keep the soil moist and prevent the plants from going dormant. However, this much water can cause regular irises to rot, so it’s best to keep your rebloomers apart from your standard irises.
Temperature and Humidity
Since reblooming iris is hardy in Zones 3-9, it tolerates a range of temperatures. Keep them in moist soil and full sun, but make sure they get afternoon shade if the weather gets very hot in your area.
Fertilizer
Use a low-nitrogen fertilizer (one with a small first number, such as 5-10-20), following package directions. To prevent burning, don’t allow the fertilizer to remain on the exposed rhizomes.Feed the plants lightly in spring as growth starts, and again in September.
Pruning
After the first bloom, sometime in late May or June, trim flower stalks from plants but leave the foliage. Repeat the process after the subsequent flowering, and if there’s another one, after it as well. Once the foliage dies back, cut back 3" from the base before winter.
Potting and Repotting Reblooming Iris
To pot reblooming iris, choose a container with drainage that’s the right size for your plant. Dwarf plants need a 6 to 8 inch diameter pot, while tall plants need a 12" diameter pot. Add some gravel or stone to the bottom of the pot to assist with drainage. If planting rhizomes, plant as you would in your garden. Place the container in a bright, sunny spot.
Pests and Problems
Like other irises, rebloomers can fall prey to iris borers and various diseases. If you spot signs of decline, talk to your county extension service about steps you need to take.
How to Propagate Reblooming Iris
Reblooming irises grow faster than regular irises, so you’ll need to divide them more often. To prevent overcrowding, divide reblooming iris every two to three years, but take only the outside rhizomes of the plant; leave the healthy older portions of the plant intact. Replant the small rhizomes 12 to 18 inches apart.
Types of Reblooming Iris
Although commonly called rebloomers, there are several types within this category, according to the Reblooming Iris Society:
“Rebloomers” (also called “remontants”) are irises that produce two or more flushes of bloom each year.“Cycle rebloomers” produce a spring crop of flowers, lie low during summer, and grow and flower again in the fall.“Repeaters” produce new flowers soon after the first spring flush dies back, extending the bloom season to one to two months.“All-season rebloomers” produce flowers irregularly throughout the season.
Most rebloomers are bearded iris, though some Siberian, Japanese, and other species offer this trait. Below are some of the most reliable reblooming bearded iris. Note: the time of bloom refers to the first flowering.
‘Autumn Bugler’
Early, tall (28 inches), purple
‘Autumn Tryst’
Early to midseason, tall (34 inches), violet and white
‘Baby Blessed’
Very early, dwarf (10 inches), light yellow
‘Bountiful Harvest’
Early, tall (33 inches), violet and white
‘Clarence’
Midseason, tall (35 inches), white and violet
‘Corn Harvest’
Early to midseason, tall (30 inches), yellow
‘Harvest of Memories’
Midseason, tall (40 inches), yellow
‘Immortality’
Midseason, tall (30 inches), white
‘Rebecca’
Midseason, tall (34 inches), rose pink
‘Sugar Blues’
Mid to late, tall (36 inches), blue
Reblooming Iris Companion Plants
Garlic
Hardy in Zones 4-9, their scent keeps animals away.
Tulips
Generally early- to mid-spring bloomers with many colors and varieties to choose from.
Peonies
This perennial with big-blooming flowers is a nice counterpoint to tall, narrow reblooming iris.
